Method of detecting sample ions by continuous electrochemical regeneration of a stationary phase

Abstract

An apparatus and method for electrochemically modifying the retention of a species on a chromatography material is disclosed. The apparatus comprises a housing having an effluent flow channel adapted to permit fluid flow therethrough. The effluent flow channel comprises chromatography material. The apparatus further comprises first and second electrodes positioned such that at least a portion of the chromatography material is disposed between the first and second electrodes, and fluid flow through the apparatus is between, and in contact with, the first and second electrodes.

We claim:  
     
       1. A method of detecting sample ions in an aqueous mobile phase while continuously electrochemically regenerating a stationary phase comprising: 
       (a) flowing the sample ions and aqueous mobile phase comprising electrolyte through a stationary phase comprising ion exchange packing material thereby at least partially exhausting the stationary phase  
       (b) during step (a) applying an electrical potential across the ion exchange packing material to electrolyze water in the acqueous mobile phase thereby generating electrolysis ions selected from the group consisting of hydronium ions and hydroxide ions;  
       (c) regenerating the at least partially exhausted stationary phase by flowing one of said electrolysis ions across the at least partially exhausted stationary phase; and  
       (d) detecting the sample ions.  
     
     
       2. The method of  claim 1  wherein the ion exchange packing material comprises ion exchange resin impregnated in a membrane. 
     
     
       3. The method of  claim 1  wherein the ion exchange packing material comprises free ion exchange resin. 
     
     
       4. The method of  claim 3  wherein the ion exchange resin comprises exchangeable cations. 
     
     
       5. The method of  claim 4  wherein the sample ions comprise cations. 
     
     
       6. The method of  claim 4  wherein the sample ions comprise anions. 
     
     
       7. The method of  claim 3  wherein the ion exchange resin comprises exchangeable anions. 
     
     
       8. The method of  claim 7  wherein the sample ions comprise anions. 
     
     
       9. The method of  claim 7  wherein the sample ions comprise cations. 
     
     
       10. The method of  claim 1  wherein water in the acqueous mobile phase is electrolyzed thereby yielding gas byproducts and comprising the additional step of removing the gas byproducts from the mobile phase prior to dection of the sample ions. 
     
     
       11. The method of  claim 10  wherein the gas byproducts are removed via gas permeable tubing located in a direction of fluid flow between the chromatography packing material and the detector. 
     
     
       12. The method of  claim 11  wherein the chromatography packing material comprises free ion exchange resin. 
     
     
       13. A method of ion chromatography wherein a stationary phase is regenerated in the presence of sample ions, the method comprising: 
       (a) flowing sample ions through a stationary phase comprising ion exchange packing material and partially exhausting the stationary phase;  
       (b) conducting electrolysis of water thereby generating electrolysis ions selected from the group consisting of hydronium ions and hydroxide ions;  
       (c) during step (a), flowing the electrolysis ions through the stationary phase thereby regenerating at least a portion of the exhausted stationary phase; and  
       (d) flowing the sample ions to a detector and detecting the sample ions.  
     
     
       14. The method of  claim 13  wherein the ion exchange packing material comprises ion exchange resin impregnated in a membrane. 
     
     
       15. The method of  claim 13  wherein the ion exchange packing material comprises free ion exchange resin. 
     
     
       16. The method of  claim 13  wherein the ion exchange packing material comprises exchangeable cations. 
     
     
       17. The method of  claim 16  wherein the sample ions comprise cations. 
     
     
       18. The method of  claim 13  wherein the ion exchange packing material comprises exchangeable anions. 
     
     
       19. The method of  claim 18  wherein the samples ions comprise anions. 
     
     
       20. The method of  claim 13  wherein the electrolysis of water yields gas by-products and comprising the additional step of preventing the gas by-products from entering the detector.